h2, body {
  padding: 0;
  margin: 0;
}
.nav-bar {
  display: flex;
  align-items: center;
  height: 40px;
  line-height: 40px;
  text-align: center;
}
.left, .right {
  width: 80px;
  flex-shrink: 0;
  background-color: red;
  height: 40px;
}
.center {
  flex: 1;
  background-color: pink;
  height: 40px;
}